Question

3sin(2a-π/4)+2cos(3a-π) если a=π/4

Answer 1

$a=\frac{\pi}{4}\\\\3sin(2a-\frac{\pi}{4})+2cos(3a-\pi )=3sin(\frac{\pi }{2}-\frac{\pi}{4})+2cos(\frac{3\pi }{4}-\pi )=\\\\=3sin\frac{\pi }{4}+2cos(-\frac{\pi}{4})=3\cdot \frac{\sqrt2}{2}+2\cdot \frac{\sqrt2}{2}=\frac{5\sqrt2}{2}$